Abstract
A table for converting Arealometer A and D readings to estimates of average fiber width (F) in micrometers and relative wall thickness (RWT) in percent is presented. The table gives “clean” estimates of F and RWT that are not obtained from A and D considered separately nor from Micronaire readings. It can be used to obtain information on the fiber properties of the large collection of cotton breeders' stocks for which Arealometer data have been recorded. A survey of over one thousand such stocks indicates that fine, medium-length fibers with relatively thick walls—a combination that may be desirable for open-end spinning—are characterized by high A and low D Arealometer readings. It is a rare combination in Upland cottons but is available in primitive forms of G. hirsutum L. and G. barbadense L. Whether this combination can be transferred to Upland cottons without reducing yield potential remains an open question.